TABLE 3.
Binding of b12 IgG to B2.1 phage mutants
| Phage clone | Peptide sequencee | IgG1 b12a
|
SDS-PAGEb
|
Western blotc b12 binding | ||
|---|---|---|---|---|---|---|
| 3 nM | 30 nM | Dimer | Monomer | |||
| B2.1 | HERSYMFSDLENRCI | 1.00 | 1.04 | + | + | + |
| B2.1-Δ Cys | HERSYMFSDLENRSI | 0.02 | 0.04 | − | + | − |
| B2.1-5′Cys | HERCYMFSDLENRSI | 0.02 | 0.05 | + | + | − |
| B2.1-CC | HERCYMFSDLENRCI | 0.03 | 0.13 | − | + | − |
| f88-4 | 0.02 | 0.03 | − | − | − | |
| None | 0.02 | 0.03 | NAd | NA | NA | |
a
Values are optical densities at 405 minus 490 nm from a direct phage ELISA.
b
Wild-type and mutant B2.1 phage were subjected to SDS-PAGE in the presence or absence of DTT; the dimer and monomer columns show the results for nontreated and DTT-treated phage, respectively. Symbols: + detection of recombinant B2.1-pVIII fusion band on silver-stained gels; − no band observed.
c
A plus sign indicates reactivity with IgG1 b12 in the Western blot, and a minus sign indicates no reactivity.
d
NA, not applicable.
e
Bold residues indicate sites at which amino acid replacements were made based on the B2.1 clone sequence.